Pumpdosimeter - system and method for automatically controlling fluid parameters in centrifugal pumps

ABSTRACT

The Pumpdosimeter is a method and apparatus for automatically maintaining a desired fluid parameter range at the sensor of a centrifugal pump system to decrease damage to the pump, and includes delivering a second pump dosage to either pipe while repeatedly sequencing through the plurality of sequential pump doses beginning with the first pump dose and proceeding to an adjacent dose in the sequence after a predetermined time interval has elapsed. The pump dosage is delivered until the fluid parameter level at the fluid parameter sensor attains the desirable range, at which point a corresponding pump dose is selected from the plurality of sequential pump doses. The method also includes delivering the selected pump dose so as to maintain the desired fluid parameter range at the fluid parameter sensor site.

CROSS REFERENCES TO RELATED APPLICATIONS

Adolph Mondry—System and method for automatically maintaining a blood oxygen saturation level. U.S. Pat. No. 5,682,877, Nov. 4, 1997—herein referred to as '877. The flow charts of that device are similar to those of the Pumpdosimeter.

Adolph Mondry—The Voltage Dosimeter—System and method for supplying variable voltage to an electric circuit. Patent application No. not yet available. The flow charts of that device are identical to those of the Pumpdosimeter.

Adolph Mondry—The Automatic Furnace—System and method for automatically maintaining a multiburner furnace. Patent application No. not yet available. The flow charts of that device are identical to those of the Pumpdosimeter.

Adolph Mondry—The Stratojet—System and method for automatically maintaining optimum oxygen content in high altitude turbojet engines. Patent application No. not yet available. The flow charts are identical to those of the Pumpdosimeter.

Adolph Mondry—The Keldosimeter—System and method for automatically maintaining comfortable minimally variable temperatures in structural and vehicular interiors indicating easy cool weather diesel engine starts. patent application No. not yet available. The flow charts are identical to those of the Pumpdosimeter.

Thomas L. Beck, Control Systems for centrifugal pumps, U.S. patent application 20040064292, herein called '292, Mar. 1, 2004.

FEDERALLY SPONSORED RECEARCH GRANTS

There are no Federally sponsored research grants available to those involved in the research and development of this device.

BACKGROUND OF THIS INVENTION

As '292 teaches, fluid parameters, such as pressure, for natural gas, oil, and water extraction must be placed in proper ranges in order to avoid damage to the centrifugal pump. The problem with placing fluid parameters automatically in an optimum range is nonlinear with a variable circulation time. It is desirable to have an automatic centrifugal pumping system that overcomes these constraints.

BRIEF SUMMARY OF THE INVENTION

It is an object of the present invention to provide a method and apparatus for automatically administering a variably powered electric centrifugal pump (delivering a pump dose) to optimize any fluid parameter—preferably pressure—in a centrifugal pump system for liquid extraction. It is a further object to optimize any fluid parameter in a centrifugal pump system for gas extraction, particularly natural gas.

In carrying out the above objects and other stated objects and features of the present invention a method and apparatus is provided as a Pumpdosimeter for maintaining a desired pressure or fluid parameter in the entrance or exit pipe at the pressure or fluid parameter sensor near the pump, and includes delivering a first pump dose from the pump and a first pressure dose to the pressure sensor-herein called a P dose, which represents a function of P (pressure) over time or a function of P over the pump power or the pump dose (abbreviated as pd), the pressure which propels the fluid through the pipe and pump, where preferably a pressure or fluid parameter sensor (herein designated as a pressure or P sensor) sends data to the ECU, producing sequential P (pressure) doses (not pump doses) at the P sensor selected from one of a plurality of P sequential doses between a first P dose and a second P dose. The method includes delivering a second dosage of the electric pump through the pipes to the P sensor while repeatedly sequencing through the plurality of sequential P doses at the P sensor beginning with the first P dose and proceeding to an adjacent P dose in the sequence after a 6 predetermined time interval has elapsed. The second pump dosage (not pressure dose) is delivered to the pipes until the P sensor attains the desirable range, at which point corresponding pump doses and P doses are selected from the plurality of pump doses and the plurality of sequential P doses. The method also includes delivering the selected pump dose to the pipes and P dose to the P sensor.

In the preferred embodiment the method and apparatus employs liquid as the main object of extraction. Gases and solids may be used as well

The advantage of the Pumpdosimeter is its ability to maintain desired fluid parameter (pressure) levels with less cost.

The above objects, features, and other advantages will be readily appreciated by one of ordinary skill in the art from the following detailed description of the best mode in carrying out the invention, when taken in connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1/6 demonstrates a perspective view of the first embodiment of the present invention.

FIG. 2/6 is a graphical demonstration of the flow charts of the Pumpdosimeter.

FIG. 3/3-5/6 are flow charts dealing with the pump dosage and P dosage and level (the latter is labeled P in the flow sheets) strategy of the present invention for use in the Pumpdosimeter.

FIG. 6/6 is a flow chart for relating parameters in the Pumpdosimeter.

DETAILED DESCRIPTION OF THE INVENTION

Referring now to FIG. 1/6, a first embodiment of the present invention is shown. This embodiment indicated by reference number 1 in FIG. 1/6 is the best mode in implementing this invention and is particularly suited for use as a Pumpdosimeter, and includes 2. a pressure sensor in the 3. entrance and 4. exit pipe. 5. a bandpass filter, 6. the ECU, and 7. a variable speed electric motor connected to the pump, which is connected to the pipes.

In response to P data 2 in or on either pipe, the electric pump is controlled by an ECU 6 controlled variable speed and power electric motor 7, analogous to the variably opening solenoid valve with Coulomb controlling circuits, as was taught in '877 and U.S. Pat. No. 5,008,773. It enhances or restricts voltage in the electric motor.

Referring now to FIG. 2/6, the method of device function is demonstrated graphically. Pressure is placed on the ordinate and time or pump dosage is placed on the abscissa of a Cartesian plane. Maximum pump dosage occurs at tr on the abscissa, the significance of which will be presented later. Measured and calculated logarithmic functions are used in the preferred embodiment as P dosages, but any measured and estimated function with an inverse may be used. The lowest logarithmic base implies the highest valued P dosage for any pump dosage value.

Referring again to FIG. 1/6, as will be seen, conditions on P at the site of the pressure sensor control pump dosage and thus the P dosage and P at the site of the pressure sensor.

Referring now to FIG. 2/6, the illustrated method of pump dosage and P dosage and level (how both can exist will be explained) selection starts at the pump with an extreme pump dosage—herein referred to as the selector dose of the pump dosage which produces the maximum or minimum P dosage at the site of radiation—as in curve A or B. Curve A is represented by y=log to the base a of x, where a is the smallest base in the system. Curve A activates at x=0.

Line CG is the desired P—herein referred to as the selection parameter, which is a range in the actual device. At the intersection of line CG and curve A or B (call it X), line D points to point E on the abscissa as the selected pump dose. This is determined by graphical means and, as will be seen, the flow charts. The virtual P dosage is curve F, which activates at point E, the selected pump dose, and is boosted by curves A, B, H—an overshoot of curve A—and curve I—a deactivation of curve H—to produce line G, which is the selected P level, and is also a dosage, and is represented by y=log to the base b of tr, where tr is the t value of the flattening out of the logarithm y=log to the base b of t (curve F) at tr seconds, and differs from tr associated with the maximum pump and P dosage used in FIG. 6/6. This tr is only used for teaching purposes. Base b is greater or equal to base a, which is associated with the maximum pump and P dosages. Line G is completely determined by the intersection (X) described above and in the flow charts, as will be seen, thus the determination of curve F and line G by the above methods is unnecessary. Curve F and line G start in the x coordinate system at x=t and in the t coordinate system at t=0, when curve A deactivates. Curve F and line G deactivate when curve A activates. Curve J is the virtual curve of curves A and H. K marks the circulation time. It marks the time from the initial maximum pump dose to the first recording of any change in the P level. Its accuracy is essential for proper flow chart function with respect to time. Its calculation and that of tr will be demonstrated. The pump dose is circulation time dependent. The P dose is not, since it is a function of time.

Before describing the flow charts it is useful to explain the terminology employed. The most recent base state keeps the temperature in its desirable range. The pressure and pump power are measured in all states. The washout state washes out overshoots. P doses are functions of pump doses and time.

Referring now to FIG. 3/6-5/6, flow charts are shown, which illustrate the system and method for the proper selection of pump and P doses and levels.

Referring to FIG. 3/6, Step 400 determines various system parameters, which may be predetermined and stored in memory, calculated by an ECU (such as ECU 4 in FIG. 1/6) or entered by a system operator. The system parameters include the following:

-   MIN R=minimum dose of pump given for each range. -   MAX R=maximum dose of pump given for each range. -   P=pressure -   POI=desired P level. -   dL=low P level threshold. -   dH=high P level threshold. -   Tss=series state delay time. -   Tcirc=circulation delay time. -   Twash=washout delay time. -   tr=desired response time or reaction time—unless otherwise stated it     is the largest value of the maximum pump dosage and the time     associated.

The value of dH and dL are pressure levels determined by the current operating state.

As shown in FIG. 3/6 the ECU now passes control to Step 402, which measures the pump dose and the P level. At Step 404 a maximum pump dose of the last range is administered. This is represented graphically by curve A of FIG. 2/6 and is called the selector dose. Curve A represents the graph of the maximum P dose as a function of the maximum pump dose. Here base a of log to the base a of x is the smallest in the system. The maximum P dose value over the maximum pump dose value is at tr. The maximum pump dose value of the maximum pump dose is tr. The possible P level is set for the lowest level of the lowest range.

With continuing reference to FIG. 3/6 at Step 406 the pump dose is maintained while pausing Tcirc seconds, then x is set to 0 seconds. Step 406 is called an adjustment state. It coordinates the flow charts with respect to time. Initial circulation times may be estimated or measured.

Referring once again to FIG. 3/6 the ECU passes control to Step 408, which continues to deliver maximum pump dosage from the pump and maximum P dosage to the sensor. Step 408 is referred to as a series state—Tss—and is necessary to coordinate the progression through various possible P levels within a time period determined by tr. The calculation of Tss depends on the current operating state. Some representative calculations are illustrated in FIG. 6/6 for a single ranged implementation as discussed in greater detail below.

Still referring to FIG. 3/6 a test is performed at Steps 409 and 410. It asks—is P greater than dH?—And, is P less than dL?, respectively. They split control into three pathways. Negative answers to both conditions direct control to Step 426, where 1. The possible P level is set to the current level, while the pump dose is set to its current abscissal level. 2. A pause for a proportionately longer or equal valued circulation time takes place. Then, 3. t is set to 0. This represents pump dose and P level or dose selection.

Now referring to FIG. 4/6 processing continues with the ECU directing control to Step 428, which pauses to washout high valued functions from the selected dose. The state is completed when all involved functions equal a straight horizontal line. Both of the above dosages continue until activation of MIN R or MAX R. FIG. 430 measures P values for the Conditions below. Steps 409 and 410 represent a second test and ask the same questions as the above mentioned first test—Is P greater than dH or less than dL, respectively? If either answer yes, control is directed to Steps 431 and 434, respectively, where a predetermined fraction of tr is either subtracted or added, respectively to tr. This pathway determines tr only if the circulation time is correct. The circulation time is calculated by keeping the last three base state values in memory. When control is directed to or beyond a noncontiguous base state from which control was originally assumed a predetermined amount of time is added to the circulation time. This will correct abnormally short circulation times. For abnormally long circulation times—if control passes consecutively to two ascending or descending base states, a predetermined amount of time is subtracted from the circulation time.

Referring now to FIG. 5/6, if both conditions in the second test answer no, the ECU places control in Step 436, the base state. Steps 438 and 440 represent the third test and ask the same questions (is P>dH or<dL?) as those of the previous tests with different consequences. They determine the stability of the base state (both conditions answer no if it is stable). If it is unstable, the ECU directs control to either Step 463, if Step 438 answers yes, or 446, which 1. Minimizes or maximizes the current dose, respectively 2. Pauses for the circulation time, then 3. Sets x=0. These doses continue until dose selection. It should be noted that Steps 431, 434, the yes part of 418, and the no part of Steps 433 and 440 all yield control to Step 436, the base state. The ECU then directs control from Step 463 to Step 411, and from Step 446 to Step 412.

Referring again to FIG. 3/6, the ECU directs control from Step 464 (evaluated later), and if Step 414 in FIG. 4/6 (the first condition of fourth test to be elucidated soon) answers no, to Step 408 to maintain the current pump and P doses for Tss. Control is then directed to Step 409, which, if along with Step 410—the first test—the answer is yes to both conditions, control is passed to Steps 411 and 412, respectively, which decrement and increment the possible dose, respectively, then both pass control to Condition 414.

Referring now to FIG. 4/6, Steps 414 and 418 represent the fourth and final test with different conditions than the other tests. These conditions ask if the present possible dose is the last dose available, and if the present range is the last one available, respectively. If Step 414 answers no, control is directed by the ECU to Step 408 in FIG. 3/6, which maintains a current dose for Tss. If the condition answers yes, control is directed to Step 418, which determines if the present range is the last range available. If it answers no, control is directed to Step 464, in which control enters a new range, sets the current pump and P doses to MAX R or MIN R of the new range, pauses for the circulation time, then sets x=0. Control is then directed to Step 408, which maintains a current pump and Pdoses for Tss. If Step 418 answers yes, the ECU directs control to Step 436, the base state.

Referring now to FIG. 6/6 a flow chart is shown illustrating representative calculations of Tss according to the present invention. One of these calculations or an analogous calculation is performed for each series state of FIG. 3/6-5/6, such as illustrated at Steps 408, 411, and 412.

Returning to FIG. 6/6 at Step 480 a test is performed to determine if the system has reached a base state. If not, the series state delay is estimated as: Tss=tr/IR. If the result is true, the process continues with Step 484, where a test is performed to determine whether P<dL. If true, then Step 486 determines whether the most recent base state is a minimum for the current range. If it is true, the series state delay is calculated by Step 488 as Tss=tr/(IR-1). Step 498 then returns control to the series state which initiated the calculation.

With continuing reference to FIG. 6/6, if the test at Step 486 is false, then the series state delay is calculated by Step 490 as Tss=tr(MAX R-MIN R)/(IR-1)(MAX R-BASE STATE) before control is released to the series state via Step 498. If the test performed at Step 484 is false, then Step 492 performs a test to determine if the most recent base state is the maximum for the current range. If the result of Step 492 is true, then Step 496 calculates the series state delay as Tss=tr/(IR-1). Control is then returned to the appropriate series state via Step 498. If the result of the test at Step 492 is false, then the series state delay is calculated by Step 494 as Tss=tr(MAX R-MIN R)/(IR-1)(BASE STATE-MIN R). Step 498 then returns control to the appropriate series state. FIG. 6/6 applies to a single range. One of ordinary skill in the art should appreciate that the calculations may be modified to accommodate a number of possible ranges.

It should be apparent to any one skilled in the art that the flow charts provide a method and apparatus for a Pumpdosimeter. 

1. A method for maintaining a desired fluid parameter level at the fluid parameter sensor at either pipe of a centrifugal pump extraction system within a predetermined range of sequential values having an upper limit and a lower limit so as to produce a predetermined fluid parameter range to reduce damage to the centrifugal pump, the method being adapted for use with a Pumpdosimeter, including an electronic control unit (ECU) having memory, a fluid parameter sensor near a variably powered electric centrifugal pump controlled by the ECU for delivering selected pump doses, producing fluid parameter doses at the fluid parameter sensor in or on the exit or entrance pipe, the fluid parameter delivery system of the Pumpdosimeter having a plurality of pump and fluid parameter doses ranging from a first dose to a second dose, the method comprising: delivering the second pump dose to the pipe and the second fluid parameter dose to the fluid parameter sensor while repeatedly sequencing through the plurality of sequential P doses beginning with the first dose and proceeding to an adjacent dose in the sequence after a predetermined time interval has elapsed until the fluid parameter sensor attains the desired level at which point a corresponding pump dosage and fluid parameter dosage are selected from the plurality of sequential fluid parameter and pump dosages. delivering the selected fluid parameter and pump doses so as to maintain the fluid parameter level at the fluid parameter sensor in its desired range.
 2. The method of claim 1 wherein the current circulation time is determined by: means for storing a predetermined number of base state values in memory; and means for determining a predetermined sequence of base state levels.
 3. The method of claim 1 wherein the reaction time is determined by logic flow charts.
 4. The method of claim 1 wherein solid, liquid, or gas may comprise the fluid parameter.
 5. A method for maintaining a desired fluid parameter level at the fluid parameter sensor at either pipe of a centrifugal pump extraction system within a predetermined range of sequential values having an upper limit and a lower limit so as to produce a predetermined fluid parameter range to reduce damage to the centrifugal pump, the method being adapted for use with a Pumpdosimeter, including an electronic control unit (ECU) having memory, a fluid parameter sensor near a variably powered electric centrifugal pump controlled by the ECU for delivering selected pump doses, producing fluid parameter doses at the fluid parameter sensor in or on the entrance or exit pipes, the fluid parameter delivery system of the Pumpdosimeter having a plurality of pump and fluid parameter doses ranging from a first dose to a second dose, the method comprising: delivering the second pump dose to the pipe and the second fluid parameter dose to the fluid parameter sensor, while repeatedly sequencing through the plurality of sequential pump doses beginning with the first dose and proceeding to an adjacent dose in the sequence after a predetermined time interval has elapsed until the fluid parameter level at the fluid parameter sensor attains the desired level at which point a corresponding pump dosage is selected from the plurality of sequential pump dosages. delivering the selected pump dosage so as to maintain the fluid parameter at the fluid parameter sensor.
 6. The method of claim 5 wherein the current circulation time is determined by: means for storing a predetermined number of base state values in memory; and means for determining a predetermined sequence of base state levels.
 7. The method of claim 5 wherein the reaction time is determined by logic flow charts.
 8. The method of claim 5 wherein the solid, liquid or gas may comprise the fluid parameter. 